Casting machine



19219- G. W. HUNG-SAY 1773395575 CASTING MACHINE Filer Sept. 1, 1926 2 Sheets-Sheet l Oct. 29, 1929. G. w. BUNGAY 1,733,576

CASTING MACHINE Filed Sept. 1926 2 Sheets-Sheet 2 KZWHWENTO M7ZZ ATTORNEY Patented Oct. 29, 1929 UNITED STATES PATENT OFFICE GEORGE W. BUNGAY, OF PLAINFIELD, NEW

JERSEY, ASSIGNOB, BY MESNE ASSIGN- MENTS, TO THE UNITED STATES ALUMINUM COMPANY, A. CORPORATION OF PENN- SYLVAN 1A CASTING MACHIN E Application filed September 1, 1926. Serial No. 133,027.

Casting machines, and in particular those known as die-casting machines, have beenoperated by hydraulics to bring together the dies between which the casting is formed. The metal to form the casting is forced between the dies under pressure and to insure a casting of the proper form it is necessary to hold the dies rigidly together. Difficulty in doing so has been experienced particularly with the larger types of machine. Increased pressure may, of course, be obtained by increasing the size of piston -and cylinder used for exerting pressure on the dies, but this means a larger and more expensive machine as well as one which must be made very much stronger in order to resist the increased pres sure. Moreover, such a larger machine would be very uneconomical because of the large amount of water which would be used by such a machine operating under high pressure.

Therefore, it is the primary ob ect of my invention to provide a novel and improved casting machine which shall embody means for intensifying the pressure exerted upon a die without the necessity of using larger machinery and the large quantities of additional fluid which would be necessary to cause the required pressure by such machinery. This object I achieve by inserting in the t This obj ectI achieve by means of the arrangement of valves, pipes and cylinders which will be more fully described later.

Referring'now to the accompanying drawings in which I have shown a selected embodito the cylinder through the check valve 20 and enters the cylinder at 21. The function ment of my invention: 4 I

Figure 1 is a side elevation of a portion of a machine having my invention applied there,- to, some elements being broken away and shown in section. Figure 2 is an end elevation of the maline hby which the fluid is supplied to the chine shown in Figure 1 as viewed from the right of that figure.

Figure 3- is a diagrammatic view of the arrangement of pipes and'valves in relation to the cylinders.

Figure 4 is a view on an enlarged scale, this .view being in part a front elevation and in part a longitudinal section, and showing the machine of Figure 1.

For the purposes of illustration I have shown and will describe my invention as applied toa die-casting machine operated by hydraulic means. It is to be understood that the invention may be employed with other fluid besides water if found desirable. A die-casting machine normally comprises a melting pot 1 heated above a furnace 2, and

containing the metal which is to be cast. In the form of machine shown there is mounted above the pot 1 the gooseneck 3 whic is pivoted at 4 whereby it may be swung into and out of the pot. When swung into t e pot it receives a charge of metal and when lifted to the position shown the nozzle 5 registers with an opening 6 between the die members 7 and 8. These two members form the die for, the casting and the metal is forced through the nozzle 5 and opening 6 into the die as is well-known in the art.

The machine is mounted upon a suitable frame work 9 whichsupports a plurality of rods 10 to which is secured thedie head 11 supporting the die member 7 Slidably mounted on the rods 10 is the die head 12 to I which is secured the die member 8. The head 12 is secured to the plate 13 which is fast on the piston 14 slidably mounted in the cylinder 15. The piston rod extends completely through the cylinder 15.which is rovided with two annular shoulders 16 and 1 These shoulders furnish stops engaging ann'ular flanges 18 and 19 res ectively on the piston to limit movement of t e piston in the cylin er.

Fluid for operating the piston is supplied of the check valve will be explained later. It

will be seen that the fluid entering the cylinder willexert pressure upon the flange 19 and will tend to cause movement of the piston towards the left as viewed in Figures 1, 3 and 4. This movement will continue until the flange 18 contacts with the shoulder 16, in which is located a port 22 connecting with a pipe 23. By this arrangement the necessityfor employing a large amount of fluid is avoided. The pressure is exerted against a flange on the piston instead of being exerted on a head of the same diameter as the cylinder. This pressure is suflicient to bring togetlier the die members by moving the member 8 to the left until it contacts with the member 7. It is necessary, however, to provide additional pressure to lock together the die members, in order to resist the force tending to separate them. This I achieve by the means which I shall now describe. Supported on the cylinder 15 is an auxiliary cylinder 24 in which is slidably mounted a piston 25. The cylinder is disposedin the line by means of which fluid is supplied to the main cylinder 15. This line comprises the pipes 26 and 27. The pipe 26 enters the head of the cylinder 24 as plainly shown and the pipe 27 is connected to the check valve 20 and to a hollow plunger 28 which is rigidly supported in a yoke 29 which may be secured to the cylinder 24 as by bolts 30, shown in Figures 1 and 2.

The piston 25 is hollow as 'shown at 31 so that it may slide upon the stationary plunger 28 having the bore 32 therein.

Referring now to Figure 3, the fluid such as water is supplied to the machine from a suitable source indicated by the pipe 33. This pipe is connected to the three-way valve 34 and to the four-way valve. 35,. Each of these valves is connected to the exhaust pipe 36 by means of which fluid which has been used in the machine may be removed. The three-way valve 34 is connected by the pipe 36 to the auxiliary cylinder 24 and by means of the pipe 37 to the check valve- 20. The valves 20, 34 and 35 may be of any usual construction and as the details per se' form no part of my invention they have not been illustrated. The four-way valve 35 is connected by the pipe 38 to the check valve 20 and by the pipe. 23 to the main cylinder 15.

In operation, aneLassuming that the die members are together as shown in Figure 1 and that the three-way valve 34is in position to open the pipes 36 and 26 and to close the pipe 33, the four-way valve 35 is then operated to admit fluid from the pipe 33 to the cylinder 15 through the pipe 23, and also to the check valve 20 through the pipe 38. The fluid entering the cylinder 15 will engage the annular flange 18 and force the piston towards the right, the fluid in the cylinder to the right of the flange 19 escaping throughthe pipe 21, check valve 20 and pipe 37 to the three-way valve 34 and thence to the wastepipe 36. A

i suitable'air valve 39 is provided for the escape of air from the cylinder 15. The check valve 20 15 so arranged that: the fluid may pass freely through the pipes 21 and 37 as just described, and so that the: fluid may pass through the pipe 38 to the pipe 27 and thus into the hollow piston 25. Therefore, at this stage the piston 25 will be forced towards the left and then all parts will have reached the approximate position shown in Figure 4.

When it is desired to bring the die members together again the four-way valve 35 is operated to connect the pipe 23 to the exhaust pipe 36 and'the three-way valve 34 is actuated to admit fluid from the pipe 33 through the pipe 26 to the cylinder 24 and also through the pipe 37 to the check valve 20 and thence through the pipe 21 to the cylinder 15. The fluid entering the cylinder 15 will exert its pressure against the flange 19' and actuate the piston 14 towards the left until the die members are brought into contact. The check valve will then be closed to prevent returning of the fluid and this closing of the valve shuts off-both pipes 37 and 38, theconne'ction between the pipes 27 and 21 remaining open. The pressure from the pipe 33 is then exerted entirely through the pipe 26 and against the head 25 of the piston 25. The force exerted on the head 25' will be transmitted to the fluid in the space 31 and thence to the end of the plunger 28. The intensity of the pressure exerted on the end of the plunger and consequently on the column of fluid in the bore 32 is several times the intensitymf pressure ex-' erted by the fluid on the head 25'. The ratio between the intensities is measured by the ratio between the area of the head 25 and the area of the end of the plunger 28,- this last area, of course, including the area of the bore 32. The ratio may be varied "as desired and between wide limits, a ratio between 6: 1 and .10: 1 having been found satisfactory.

Obviously the pressure in the bore 32 will be transmitted through the pipes 27 and 21 to thecylinder l5 and will be exerted against the flange 19. This pressure will lock the' die member securely together during the casting operation. Furthermore this intensified pressure is used merely to bring the die members securely together and to hold them there without being wasted in actuating the piston 14 during its main movement. This main movement in both directions is caused by a relatively low pressure which may be regulated as. desired so as to be most economical.

It will be noted'that the piston 14 is actuated solely by pressure against a relatively small area thereon. The usual large head is entirely avoided, which head, working in a cylinder, requires a large amount of fluid to operate the piston. By the construction shown a great economy in use of actuating fluid such as water is efl'ectedQ Moreover, it will be obvious that, in order to apply to the piston the same pressure as obtained with the auxiliary cylinder and piston ate said piston in said cylinder, an auxiliary cylinder connected to a source of fluid supply and to said main cylinder, and a piston in said auxiliary cylinder having means to intensify the pressure of said fluid and to transmit the intensified pressure to the main cylinder.

2. A casting machine comprising a die member, a piston to which said member is connected, a main cylinder slidably supporting said piston, an auxiliary cylinder having an outlet connection to said main cylinder, a hollow piston in said cylinder and having the hollow space therein connecting with said outlet, and means for supplying fluid to said auxiliary cylinder to exert pressure on the head of said hollow piston and-to force fluid contained therein through said outlet connection to said main cylinder.

3. A casting machine comprising a cylin-' der, a piston comprising a piston rod slidably indunted in said cylinder and spaced from the walls thereof and extending entirely therethrough, aflange on said piston rod and disposed in said cylinder between the piston rod and the walls of said cylinder, means for exerting fluid pressure against said flange to actuate said piston, and means to intensify said pressure prior to the casting operation.

4. A casting machine comprising a die member, a piston to which said member is connected, a cylinder in which said piston is slidably mounted, means to "admit fluid under pressure to said cylinder to actuate said piston, and auxiliary means to intensify said pressure prior to the casting operation.

5. A casting machine comprising a die member, a piston to which said member is connected, a main cglindersl-idably supporting said piston, flui pressure means to actuate said piston in said cylinder, an auxiliary cylinder connected to a source of fluid supply and to said main cylinder, a piston in said auxiliary cylinder having means to intensify 6. A casting machine comprising a die a member, a piston to which said member is connected, a main cglinder slidably supporting said piston, flui pressure means to actuate said piston in said cylinder, an auxiliary cylinder connected to a source of fluid supply and to said main cylinder, a piston in said auxiliary cylinder having means to in-. tensify the pressure of said fluid and to transmit the intensified pressure to the main cylinder, means to operate said fluid pressure means, and means to discontinue said operation and to operate said intensifying means.

7. A casting machine. comprising a main cylinder having a piston slidably mounted therein, an auxiliary cylinder connected to said main cylinder, means in said auxiliary cylinder to intensify the pressure of fluid in said main cylinder, means connecting a source of fluid supply to both of said cylinders and a check valvethrough which fluid passes from said source to said main cylinder and from said auxiliary cylinder to said main cylinder, said valve having means whereby fluid at normal pressure is permitted to pass from said source to said main cylinder and fluid at intensified ressure is permitted to pass to said main cylinder from said auxiliary cylinder.

In testimony whereof, I have aflixed my signature to this s eciflcation. 

